In the related art, there has been a vehicle seat device in which air bags (bladders) provided inside a seat are expanded, thereby bulging a seat surface so that the support shape of the seat can be changed. For example, a seat device disclosed in JP 03-032943A (Reference 1) includes a plurality of air bags provided inside a seat back, at a position on which the waist portion (lumbar) of an occupant seated on the seat is abutted. Specifically, the air bags are arranged to be aligned in the vertical direction so as to follow the backrest face of the seat back. By sequentially expanding and contracting the air bags along the arrangement direction, it is possible to vertically move the bulging shape formed by each corresponding air bag on the seat surface, that is, the position of a lumbar support shape.
However, in the case of the air pressure type seat device as described above, the larger the amount of protrusion of the bulging shape formed by the expanded air bag on the seat surface, the larger the amount of air pumped into the air bag. That is, when the air bag in a contracted state is expanded, the time until the bulging shape formed on the seat surface reaches the required amount of protrusion becomes long. Accordingly, when the formation position of the bulging shape is moved by sequentially expanding and contracting the air bags as described above, there is a problem in that the time required for the movement of the corresponding bulging shape varies depending on the amount of protrusion of the bulging shape. In this respect, there is still room for improvement.
Thus, a need exists for an air pressure control device of a vehicle seat and an air pressure control method of the vehicle seat which are not susceptible to the drawback mentioned above.